The present invention relates to a semiconductor device and a method for manufacturing the same, and more particularly, to a semiconductor device that prevents storage nodes from leaning and cracks from occurring in support patterns and a method for manufacturing the same.
The rapid increase in demand for semiconductor memory devices has lead to various attempts to develop techniques for obtaining a high capacitance capacitor. Typical capacitors have a structure in which a dielectric layer is interposed between storage nodes and plate nodes. The capacitance of the capacitor is directly proportional to the surface area of an electrode and the dielectric constant of the dielectric layer and is inversely proportional to the distance between electrodes, i.e., the thickness of the dielectric layer.
Therefore, in order to obtain a capacitor having a high capacitance, it is necessary to use a dielectric layer having a high dielectric constant, increase the surface area of an electrode, or decrease the distance between electrodes. From among these methods, decreasing the distance between electrodes, i.e., the thickness of the dielectric layer, is limited. Therefore, research for forming a capacitor having a high capacitance is primarily directed toward using a dielectric layer having high dielectric constant or increasing the surface area of an electrode by increasing the height of the capacitor.
A conventional method for increasing the surface area of an electrode forms a capacitor as a concave type or a cylinder type. In comparing the two types, the cylinder type capacitor has a wide surface area of an electrode when compared to the concave type capacitor because the inner surface and the outer surface of a storage node can be utilized as the surface area of an electrode. Therefore, the cylinder type capacitor may be advantageously applied to a highly integrated semiconductor device.
In order to form the cylinder type capacitor, a dip-out process for removing a mold insulation layer, which served as a mold for forming storage nodes, should be conducted. Considering the size of a cell is decreasing in order to accommodate the trend toward highly integrated semiconductor devices, the aspect ratio of the storage nodes increases and the gap between the storage nodes becomes narrow as a result. Due to the increasing aspect ration and the narrowing gap, the storage nodes are likely to lean when conducting the dip-out process. In order to overcome this drawback, a method for forming support patterns to fix the storage nodes has been suggested in the art.
Nevertheless, in the conventional art, cracks are likely to occur in support patterns due to the high tensile stress (ranging 1×109˜1×1010 dyne/cm2) of a nitride layer used under a low-pressure condition to form the support patterns. As a result, a dielectric layer may not be uniformly formed where the cracks occur when subsequently forming the dielectric layer. Because of this, in the conventional art, the voltage discharge characteristic of the capacitor is deteriorated and leakage capacitance occurs, whereby the characteristics and reliability of a semiconductor device can be degraded as a result.